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Objectives: The purpose of the present study was two-fold: (1) To analyse physical fitness changes of youth football players after a full-season; and (2) to examine whether physical fitness changes are explainable by estimated maturity status, 2digit:4digit ratio (2D:4D) from each hand and training load (TL) measures., Methods: Twenty-seven youth elite Under-15 football players were daily monitored for training load measures during 38 weeks. At the beginning and at the end of the season, all players were assessed for physical fitness. Also, the maturity status estimation and the length of the second and fourth digits of both hands were collected at the beginning of the season., Results: Significant differences were found for all physical fitness measures after the season. The second and fourth digits of left and right hands had negative moderate correlations with change of direction (COD) changes (r=-.39 to - 0.45 | p = .05 to 0.02). Also, the maturity offset measure had negative moderate correlations with COD changes (r=-.40 | p = .04). From the reported significant correlations, the maturity offset, Left 4D, Right 2D and Right 4D significantly predicted the Mod.505 COD test changes (β = 0.41, p = .04; β = -0.41, p = .04; β = -0.45, p = .02; and β = -0.44, p = .03, respectively)., Conclusion: The maturity offset and the 2D:4D measures have the potential to predict COD performance changes over-time in youth football players. Given the lack of associations between the maturity estimation, 2D:4D and training load measures, with the overall physical fitness measures, coaches should rely only at COD changes., (© 2022. The Author(s).)

Objective: This review aims to explore the potential of implicit learning to enhance football performance under psychological pressure. The focus is on examining how implicit learning might mitigate the negative effects of pressure and improve the consistency and effectiveness of football skills during high-stakes situations. Materials and Methods: A systematic search strategy was employed to gather relevant research from databases such as SPORTDiscus, PsycINFO, PubMed, Google Scholar, and Web of Science. Keywords included "implicit learning," "motor skills," "football," "pressure performance," and "choking under pressure." The review considered peer-reviewed articles published in English, focusing on studies that investigated the relationship between implicit learning and football performance under pressure. Results: Implicit learning, characterized by the unconscious acquisition of skills through repeated practice, shows promise in enhancing football performance under pressure by promoting automaticity and reducing cognitive load. Studies have demonstrated that implicit learning can lead to more automatic and smoother motor skills, potentially making them less susceptible to disruption by pressure. Evidence from research on penalty kicks and other football-related tasks supports the effectiveness of implicit learning in high-pressure situations. Conclusion: The review highlights the potential of implicit learning to buffer the effects of psychological pressure in football, promoting resilience and adaptability in high-stakes scenarios. Further research is needed to optimize training methods for implicit learning and explore its application across different football skills and pressure conditions. Integrating implicit learning strategies into football training programs could equip athletes with the mental tools to perform at their peak under pressure. [ABSTRACT FROM AUTHOR]

The present study was intended to i) investigate the relationship between metabolic power average (MPA), acceleration (AcZ) and deceleration (DcZ) zones, and their differences (Δ) on 3 load levels with noncontact injuries in professional players throughout a full soccer season and ii) to analyze the injury risk associated between high-load versus low-load levels for each of the aforementioned parameters with odds ratios (OR) and relative risk (RR), respectively. Twenty-one professional soccer players (age = 28.3 ± 3.9 years) were monitored during a full season (48 weeks) through global positioning system (GPS). A relationship between MPA and accelerometer-based GPS, mainly in explosive actions (i.e., AcZs and DcZs), was found. A higher incidence of injuries in the high-load weeks compared with the low-load weeks were reported (mainly in MPA, AcZ1, AcZ2, and DcZ3 variables). Moreover, significant means of OR (mean = 4.3) and RR (mean = 2.6) of noncontact injuries were established in intense periods with higher metabolic load (i.e., power accelerations, AcZ1, x² = 0.022). Our results may be useful for coaches, sports scientists, and researchers regarding the optimization of the athletes' performance, as well as providing insights about the impact of intense exercise. [ABSTRACT FROM AUTHOR]

Background: Performance in jumping and change of direction tests are good proxies to reflect the skill level during soccer-specific actions. Greater inter-leg asymmetries have been identified as a risk factor for developing acute and overuse injuries and jeopardizing soccer performance. The aim of this study was to assess the association between asymmetry in the unilateral vertical and horizontal jump tests, ankle range of motion, linear velocity, and change of direction in a sample of highly trained adult female soccer players. Methods: Thirty-eight highly trained female soccer players underwent a testing protocol including ankle dorsiflexion, single leg jumps for height (CMJ), distance (HJ), 40 m sprint and 180° change of direction tests. Results: Within-session reliability was acceptable (CV ≤ 7.9%), and relative reliability showed good to excellent (ICC: 0.83 to 0.99). The one-way ANOVA reported higher inter-limb differences for change of direction deficit (10.9 ± 8.04%) and single leg CMJ (5.70 ± 5.22%). Pearson correlations highlighted significant relationships between horizontal jump asymmetries and ankle dorsiflexion (r = -0.41), CMJ (r = -0.36 to -0.49) and HJ (r = -0.28 to -0.56). Conclusions: Assessing inter-limb asymmetries through different methods can help scientists understand the specificity of their detrimental effects on soccer performance. Practitioners should be aware of these specificities as well as the magnitude and direction of the asymmetries when aiming to improve specific on-field skills. [ABSTRACT FROM AUTHOR]

Purpose. The study aim was 2-fold: to quantify and compare the weekly external training load that preceded matches; to compare in-match activities depending on the opponent level (top, middle, bottom) in a top-level team from the first professional Asian national league. Methods. The load for 6 matches played against top-, 11 against middle-, and 11 against bottom-level teams was monitored. With a 15-Hz Global Positioning System, total duration, total distance, high-speed (18-23 km · h-1) running distance, sprint (> 23 km · h-1) distance, maximal speed, acceleration zone 1 (AccZ1) (< 2 m · s-2), AccZ2 (2-4 m · s-2), AccZ3 (> 4 m · s-2), deceleration zone 1 (DecZ1) (> -2 m · s-2), DecZ2 (-2 to -4 m · s-2), DecZ3 (< -4 m · s-2), player load, and metabolic power were collected in 12 players. Results. DecZ3 showed higher values against top-level compared with middle- (effect size [ES] = 0.91) and bottom-level opponents (ES = 1.50). The training was significantly longer against middle-level compared with top- and bottom-level opponents (all, p 0.001). Total distance was bigger against middle-level compared with top- (p = 0.011, ES = -0.92) and bottom-level opponents (p = 0.027, ES = 1.50). AccZ2 presented higher values when middle-level came close compared with bottom-level opponents (p = 0.05, ES = 0.79). Conclusions. Opponent's level influences the load experienced by soccer players during matches. Total distance, highspeed running distance, AccZ1, and AccZ2 exhibited higher training values when a win or a draw approached. Decelerations in all zones were highest in matches against top-level teams. [ABSTRACT FROM AUTHOR]

Purpose. The study compared the change-of-direction deficit (CODD) using the first 10-m sprint of a 40-m sprint test (CODDoriginal), the 10-m time that precedes the 5-0-5 test (CODD5-0-5start), and the best 10-m split of a 40-m sprint test (CODDbest). Results. The time over 10 m during the 30-40-m split of a 40-m sprint test was significantly shorter than the first 10 m of the same sprint test (best times: p < 0.001, d = -7.077; average time: p < 0.001, d = -1.140) and the first 10-m acceleration phase of the 5-0-5 test (best times: p < 0.001, d = 9.000; average times: p < 0.001, d = -8.500). No significant differences were found between the first 10 m of the 40-m sprint test and the 5-0-5 test (best times: p > 0.999, d = 0.133; average times: p = 0.990, d = 0.047). Comparisons of CODD revealed significant differences between approaches (best times: F = 201.7, p < 0.001, p 2 = 0.914; average times: F = 196.2, p < 0.001, p 2 = 0.912). However, there were no significant correlations between any CODD outcomes and the 40-m sprint test (p > 0.05). Conclusions. CODD calculated with the first 10 m and the best 10 m of a sprint test was significantly different; similarities existed between the initial 10 m of a 40-m sprint test and the 5-0-5 test. Therefore, to save time and resources, practitioners could use the first 10-m acceleration phase of the 5-0-5 since no significant differences were found between the initial 10 m of a linear sprint test. [ABSTRACT FROM AUTHOR]

Simple Summary: Scientific research has demonstrated that puberty status has a crucial influence on soccer players, and their energy demands are primarily determined by their aerobic capacity. In our investigation, we examined the relationships between maturation variables such as peak height velocity (PHV) and maturity offset with variations in accumulated-training load parameters and locomotor demands in elite young soccer players; the aim was to predict the percentage of changes in their performance ability with adjustments to the training load parameters considering maturation variables. Our study's main findings revealed a link between accumulated-training load parameters and locomotor demands. In addition, the acute:chronic workload, training monotony, and PHV values explained aerobic power performance. This study offers new valuable insights into the practice of accumulation and motor demand in young elite players. The study's purposes were to examine the associations of training load parameters with locomotor demand and puberty status in elite young soccer players and to predict the percentage of changes in their performance ability with adjustments to the training load parameters, using multivariate regression analysis, while considering PHV and maturity offset. Seventeen male players (15–16 years old) participated in this study. Anthropometrics, body composition, maximal oxygen consumption (VO2max), and puberty status (for calculating PHV) and maturity offset were assessed. The results demonstrated substantial differences between the PHV, VO2max, and load parameters (acute and chronic workload (CWL)) over a soccer season. A substantial relationship existed between the workload parameters (VO2max, CWL, and training monotony (TM)) and maturity offset. All of the variables, except for training strain, demonstrated significant variances in relation to the differences between the first and second halves (p < 0.05). Aerobic performance can be estimated using the CWL, TM, and maturity offset values (R2 = 0.46). On the contrary, aerobic power performance can be explained using the acute:chronic workload, TM, and PHV values (R2 = 0.40). In conclusion, the biological maturity state of young soccer players has a substantial impact on their functional potential. Variations in accumulated load contribute significantly to aerobic resistance, whereas weight and height contribute significantly to sprint and vertical-jump performance, respectively. [ABSTRACT FROM AUTHOR]

The purpose of this study was (i) to compare two groups (players with more vs. less match play time) regarding body composition, vertical and horizontal jumping performance, and aerobic capacity; and (ii) to test the relationships between physical fitness and play time. This study followed a case-control design in which the outcome was playtime, and the causal attribute was physical fitness. Sixty-six youth male soccer players from under-16 (n = 21), under-17 (n = 19), under-18 (n = 12), and under-19 (n = 14) age groups were monitored for match play time during five months of observation. Inclusion criteria consisted of (1) no absence of more than a week due to injury or other conditions during the five months of observation and (2) physical assessments having been done simultaneously with those of the other players (at the beginning of the season). The exclusion criteria were (1) not participating in one week or more of training sessions, and (2) not participating in the physical fitness assessments. At the beginning of the season, players were assessed for anthropometry (height, body mass, skinfolds), countermovement jump, triple hop bilateral and unilateral jump, and aerobic capacity using the Yo-Yo Intermittent Recovery Test, level 2 (YYIRT). The group that played more time had significantly greater YYIRT results (+28.2%; p = 0.009; Cohen's d = 0.664). No other significant differences were found between those who played more and fewer minutes. Moderate and significant linear positive correlations were found between YYIRT and play time in the under-19 group (r = 0.423; p = 0.031) and overall (r = 0.401; p < 0.001). In the case of the under-17 group, moderate and significant linear positive correlations were found between TSA and play time (r = 0.473; p = 0.041). This suggests that aerobic and anaerobic capacity is related to play time while jumping performance and fat mass seem not to play an essential role in play time. [ABSTRACT FROM AUTHOR]

Injuries in professional soccer are a significant concern for teams, and they are caused amongst others by high training load. This cohort study describes the relationship between workload parameters and the occurrence of non-contact injuries, during weeks with high and low workload in professional soccer players throughout the season. Twenty-one professional soccer players aged 28.3 ± 3.9 yrs. who competed in the Iranian Persian Gulf Pro League participated in this 48-week study. The external load was monitored using global positioning system (GPS, GPSPORTS Systems Pty Ltd) and the type of injury was documented daily by the team's medical staff. Odds ratio (OR) and relative risk (RR) were calculated for non-contact injuries for high- and low-load weeks according to acute (AW), chronic (CW), acute to chronic workload ratio (ACWR), and AW variation (Δ-Acute) values. By using Poisson distribution, the interval between previous and new injuries were estimated. Overall, 12 non-contact injuries occurred during high load and 9 during low load weeks. Based on the variables ACWR and Δ-AW, there was a significantly increased risk of sustaining non-contact injuries (p < 0.05) during high-load weeks for ACWR (OR: 4.67), and Δ-AW (OR: 4.07). Finally, the expected time between injuries was significantly shorter in high load weeks for ACWR [1.25 vs. 3.33, rate ratio time (RRT)] and Δ-AW (1.33 vs. 3.45, RRT) respectively, compared to low load weeks. The risk of sustaining injuries was significantly larger during high workload weeks for ACWR, and Δ-AW compared with low workload weeks. The observed high OR in high load weeks indicate that there is a significant relationship between workload and occurrence of non-contact injuries. The predicted time to new injuries is shorter in high load weeks compared to low load weeks. Therefore, the frequency of injuries is higher during high load weeks for ACWR and Δ-AW. ACWR and Δ-AW appear to be good indicators for estimating the injury risk, and the time interval between injuries. [ABSTRACT FROM AUTHOR]

Background: Small-sided games (SSGs) are drill-based and constrained exercises designed to promote a technical/tactical and physiological/physical stimulus on players while preserving some dynamics of the real game. However, as a dynamic game, they can offer some variability making the prediction of the stimulus hardest for the coach. Aim: The purpose of this study was to analyze the between-session and within-player variability of heart rates and locomotor responses of young male soccer players in 3v3 and 5v5 small-sided game formats. Methods: This study followed a repeated-measures study design. Twenty soccer players were enrolled in a study design in which the SSG formats 3v3 and 5v5 were performed consecutively across four days. Twenty under-17 male youth soccer players (16.8 ± 0.4 years old) voluntarily participated in this study. Participants were monitored using a Polar Team Pro for measuring the heart rate mean and maximum, distances covered at different speed thresholds, and peak speed. Results: Between-players variability revealed that maximum heart rate was the outcome with a smaller coefficient of variation (3v3 format: 3.1% to 11.1%; 5v5 format: 6.6% to 15.2%), while the distance covered at Z5 (3v3 format: 82.5% to 289.8%; 5v5 format: 94.0% to 221.1%). The repeated measures ANOVA revealed that the four games tested were different in the within-player variability considering the maximum heart rate (p = 0.032), total distance (p < 0.001), and distances at zone 1, 2, and 5 of speed (p < 0.001). Conclusions: The smaller small-sided game tested promotes greater within-player variability in locomotor demands while promoting smaller within-player variability heart rate responses. Possibly, 5v5 is more recommended to stabilize the locomotor demands, while the 3v3 is recommended to stabilize the heart rate stimulus. [ABSTRACT FROM AUTHOR]

Simple Summary: Soccer performance is complex, requiring mastery of sport specific technical and tactical skills with ideal physical fitness (i.e., includes sprints, hops, accelerations, changes of directions, and so on) and body composition (i.e., increase lean muscle mass and decrease fat mass). In the last decades, performance models have helped to understand the multifactorial mechanisms involved in physical performance in sports. Hence, we tested the hypothesis that a neuromuscular training (NMT) program has an effect on body composition parameters in elite female soccer players. The result showed that implementation of 10-week with thrice-weekly NMT program improves body composition in elite female soccer players. (1) Background: This study was conducted to investigate the effects of a 10-week neuromuscular training program (NMT) on the sum of six skinfolds (Σ6S) and body composition variables in elite female soccer players. (2) Methods: Forty-four Spanish elite female soccer players (age: 24.0 ± 4.2 years; height: 164.3 ± 5.5 cm; body mass: 60.4 ± 5.5 kg; body mass index (BMI): 22.4 ± 2.2 kg/m2) were randomly assigned to a control group (CG) or to an experimental group (EG). Participants in the EG completed a specific NMT program of 24 min, three times per week, which included exercises from six different categories (mobility, dynamic stability, anterior chain strength, lumbopelvic control, posterior chain strength, and change of direction). The CG followed their normal strength and conditioning program. Pre- and post-intervention assessments included anthropometric measurements (weight, height, limb circumferences, and bone breadths), and subsequently, body composition factors BMI, Σ6S, body mass, muscle mass, and lean body mass were calculated. Nutrition was standardized by a nutritionist and also load monitored. (3) Results: A two-way mixed analysis of variance (group × time) revealed that there was a significant (p ≤ 0.001) group × time interaction between body mass, fat mass, and Σ6S in favor of NMT. A significant interaction was also observed for body skeletal muscle mass and lean body mass favoring NMT. (4) Conclusions: The application of an NMT program seems to be a useful strategy to improve body composition in elite female soccer players. [ABSTRACT FROM AUTHOR]

Background: The main aim of this study was to evaluate the relationships between training workload (WL) parameters with variations in the change of direction (COD) in under-16 soccer players. Methods: Twenty-seven under-16 elite soccer players were daily monitored for their WL across 15 weeks during the competitive soccer season. Additionally, players were assessed two times for anthropometric measures (weight, height, sitting height and leg length), COD performance (modified 505 test) and maturity offset measured using the peak height velocity (PHV). Results: A correlational analysis was performed to determine the relationship between the variation in COD performance and accumulated WL parameters. Moreover, a regression analysis was executed to explain the variations in the percentage of COD performance considering the accumulated WL parameters and PHV of the season (r = 0.93; p ≤ 0.01) and training monotony during the early-season (r = 0.53; p ≤ 0.05). There were associations between the acute workload during the start of the season and the COD during the end of the season (r = 0.47; p ≤ 0.05). The multiple linear regression analysis showed that 55% of the variation in COD performance between the early and end of season could be explained by the acute or chronic WL, training monotony or strain and the PHV. Conclusions: This information might be useful for practitioners and coaches aiming to improve the COD performance in youth soccer players during an entire competitive season. [ABSTRACT FROM AUTHOR]

Although data currently exists pertaining to the intensity in the women's football match, the knowledge about training is still scarce. Therefore, the aim of this study was to quantify external (locomotor activity) and internal (psychophysiological) intensities, as well as the wellness profile of the typical microcycle from professional female soccer players during the 2019/20 in-season. Ten players (24.6 ± 2.3 years) from an elite Portuguese women soccer team participated in this study. All variables were collected in 87 training session and 15 matches for analysis from the 2019–2020 in-season. Global positioning variables such total distance, high-speed running, acceleration, deceleration and player load were recorded as intensity while Rated Perceived Exertion (RPE) and session-RPE were recorded as internal measures. The Hooper Index (HI) was collected as a wellness parameter. The results showed that internal and external intensity measures were greater in matches compared to trainings during the week (match day minus [MD-], MD-5, MD-4, MD-2), p < 0.05 with very large effect size (ES). In the same line, higher internal and external intensity values were found in the beginning of the week while the lowest values were found in MD-2 (p < 0.05, with very large ES). Regarding wellness, there was no significant differences in the HI parameters between the training days and match days (p > 0.05). This study confirmed the highest intensity values during MD and the lowest on the training session before the MD (MD-2). Moreover, higher training intensities were found in the beginning of the training week sessions which were then reduced when the MD came close. Wellness parameters showed no variation when compared to intensity measures. This study confirmed the hypothesis regarding internal and external intensity but not regarding wellness. [ABSTRACT FROM AUTHOR]

The aim of this study was to describe weekly acute workload (wAW), chronic workload (wCW), acute: chronic workload ratio (wACWR), training monotony (wTM), and training strain (wTS) variations over a full season across playing positions. Twenty-one professional soccer players were daily monitored during 48 consecutive weeks. Total distance, sprint total distance (STD), high-speed running distance (HSRd), maximum speed, number of the repeated sprints, and body load (BL) were obtained during training and matches using a Wearable Inertial Measurement Unit. The wAW was determined for each external load measure. The wCW, wACWR, and wTM were calculated based on BL metric. Higher values of weekly STD were observed in lateral defenders/wingers (LDW) compared to central defenders/forwards (CDF) (p = 0.009; ES = Large) and midfielders (MDF) (p = 0.034; ES = Large). Additionally, weekly HSRd was higher in LDW vs. CDF (p = 0.016; ES = Large) and MDF (p = 0.011; ES = Large). The CDF presented a lower weekly number of repeated sprints than LDW (p = 0.021; ES = Large). In conclusion, weekly external load metrics were position-dependent over the season. Moreover, LDW a presented greater weekly STD, HSRd, and number of repeated sprints compared to other positions. [ABSTRACT FROM AUTHOR]

The aims of this study were to analyze the within-group weekly metabolic power average (wMPA), weekly acceleration zones (wAcZ), and weekly deceleration zones (wDcZ), in starter and non-starter professional soccer players, based on different periods of the full season (pre-, early-, mid-, and end-season). Twenty-one professional soccer players (age, 28.3 ± 3.8 years; height, 181.2 ± 7.1 cm; body mass, 74.5 ± 7.7 kg; BMI, 22.6 ± 1.0 kg·m2) were monitored during the full season in the highest level of the Iranian Premier League. WMPA, wAcZ, and wDcZ at three different zones (wAcZ1, wAcZ2, wAcZ3, wDcZ1, wDcZ2, wDcZ3) were collected using Global Positioning System. ANOVA was applied to analyze within-group changes across the different periods of the full season. In general, starters presented higher values in the beginning of the season (pre- and early-season) and lower values at mid- and end-season. Specifically, starters showed significant differences in early- vs. mid-season for wMPA, wAcZ1, and wDcZ1 (p < 0.05), plus early- vs. end-season for wMPA and wAcZ1 (p < 0.01). In addition, non-starters showed higher values in the pre-season that decreased until the end-season for wMPA, wAcZ1, and wDcZ1. Regarding wAcZ2, wDcZ2, wAcZ3, and wDcZ3, non-starters presented higher values in early-season that decreased until the end-season. Specifically, non-starters showed significant differences in pre- vs. mid-season for wMPA, wAcZ1, and wDcZ1; pre- vs. end-season for wMPA, wDcZ1, wDccZ2, and wDcZ3; early- vs. mid-season for wMPA, wAcZ1, wDcZ1, wAcZ2, and wDccZ2; early- vs. end-season for wMPA, wAcZ1, wDcZ1, wAcZ2 wDccZ2, wAcZ3, and wDcZ3; and mid- vs. end-season for wMPA, wAcZ1, and wAcZ3 (p < 0.05). In conclusion, starters were revealed to have higher values in pre- and early-season, and lower values in mid- to end-season, while non-starters were revealed to have lower load values in pre- and end-season and higher load values in early- and mid-season. This study provides extra insights over the season for starters and non-starters, respectively. Data can be used by coaches to better training periodization across soccer season. [ABSTRACT FROM AUTHOR]

This study sought to analyze the relationship between in-season training workload with changes in aerobic power (VO2m ax ), maximum and resting heart rate (HR max and HR rest ), linear sprint medium (LSM), and short test (LSS), in soccer players younger than 16 years (under-16 soccer players). We additionally aimed to explain changes in fitness levels during the in-season through regression models, considering accumulated load, baseline levels, and peak height velocity (PHV) as predictors. Twenty-three male sub-elite soccer players aged 15.5 ± 0.2 years (PHV: 13.6 ± 0.4 years; body height: 172.7 ± 4.2 cm; body mass: 61.3 ± 5.6 kg; body fat: 13.7% ± 3.9%; VO2m ax : 48.4 ± 2.6 mL⋅kg–1⋅min–1), were tested three times across the season (i.e., early-season (EaS), mid-season (MiS), and end-season (EnS) for VO2m ax , HR max , LSM, and LSS. Aerobic and speed variables gradually improved over the season and had a strong association with PHV. Moreover, the HR max demonstrated improvements from EaS to EnS; however, this was more evident in the intermediate period (from EaS to MiS) and had a strong association with VO2m ax . Regression analysis showed significant predictions for VO2m ax [ F (2,20) = 8.18, p ≤ 0.001] with an R 2 of 0.45. In conclusion, the meaningful variation of youth players' fitness levels can be observed across the season, and such changes can be partially explained by the load imposed. [ABSTRACT FROM AUTHOR]

The purposes of this study were (i) to analyze the variations in maximal oxygen consumption (VO2max), maximal heart rate (HRmax), heart rate at rest, acceleration, maximal speed, agility, anaerobic sprint test (RAST) of peak power (RPP), RAST of minimum power, RAST of average power (RAP), and RAST of fatigue index (RFI) during the competitive season, using maturation status and accumulated training load as covariates, and (ii) to describe the differences between responders and non-responders in relation to baseline levels. Twenty-three elite players from the same team competing in the national under-16 competitions were evaluated for 20 weeks in period 1 (before league), middle (mid league), and period 2 (after league). The VO2max (p = 0.009), maximal speed (p = 0.001), RPP (p < 0.001), RAP (p < 0.001), and RFI (p < 0.001) significantly changed across the assessment periods. Interestingly, using accumulated training load and maturation status as covariates revealed no statistical significance (p > 0.05). When analyzing responders and non-responders, only HRmax (between periods 1 and 2) showed no differences between the groups. As a conclusion, it can be seen that accumulated training load and maturation status play an important role in the differences observed across the season. Thus, coaches should consider the importance of these two factors to carefully interpret fitness changes in their players and possibly adjust training decisions according to the maturation level of the players. [ABSTRACT FROM AUTHOR]